Golf clubs, combined with golf balls, have generally been considered to be the most essential equipment in the game of golf. Progressing in parallel with the development of the game of golf, significant developments have occurred within the golf equipment industry. Golf clubs, especially wedge type golf clubs, have also developed simultaneously with all other types of golf equipment to accommodate for the needs of the golfer to hit their shots more accurately and with more control.
Wedge type golf clubs, more commonly known as wedges, are a particular type of golf club that generally has a higher loft angle. These higher lofted wedges tend to be precision instruments that allow a golfer to dial in short range golf shots with improved trajectory, improved accuracy, and improved control. This increased loft angle in wedges generally yield a golf shot with a higher trajectory because of the impact surface with the golf ball is not perpendicular to the trajectory of the club head; but rather, the golf ball interacts with the wedge at an inclination closely resembling the actual loft angle of the wedge itself. This inclination generally causes the golf ball to move up along the inclination of the wedge when struck by the wedge type golf club head, creating a backward rotation of the golf ball as it leaves the wedge club face. This backwards rotation of the golf ball is generally known as “backspin” within the golf industry; and it is desirable in helping improve trajectory, accuracy, and control of a wedge type golf shot.
Backspin helps improve trajectory, accuracy, and control of a golf shot by giving the golf ball a gyroscopic effect, which stabilizes ball flight, hence increasing accuracy. Moreover, backspin also serves to increase control of a golf shot as backspin minimizes the roll of a golf ball after landing, creating a more predictable golf shot even after it lands on the ground.
A number of methods are generally known in the golf club art to increase backspin. For example, one method to generate increased backspin may be increasing the coefficient of friction of the wedge club face. U.S. Pat. No. 5,804,272 to Schrader titled Backspin Sticker ('272 patent) generally discloses a combination of a backspin sticker and a golf club having an angled surface for increasing the backspin of a golf ball when it hits the putting surface. More specifically, the '272 patent discloses a sticker, shaped to conform to a hitting area on the hitting surface, the sticker having a front surface with a coating of silicon carbide grain affixed with a synthetic resin and an adhering region having a clear, pressure sensitive adhesive applied thereon.
U.S. Pat. Pub. No. US 2004/0127300 to Roesgen et al. titled Golf Clubhead ('300 patent publication) is another example of a methodology used to increase backspin of a wedge type golf club by increasing coefficient of friction of the wedge club face. The '300 patent publication generally discloses a golf clubhead made from metal, having a strike face which has a loft angle α of greater than 45°, the strike face having a plurality of parallel grooves, where the strike face has a surface roughness Ra of less than 0.25 micrometer, and a Vickers hardness of the strike face greater than 5 GigaPascal.
Although the surface treatments discussed above may be effective in increasing the backspin of a golf ball, surface treatments often suffer from gradual wear and tear, making them less optimal. In order to address that issue, U.S. Pat. No. 7,014,568 to Pelz for a Golf Club ('568 patent) discloses a wedge face groove configuration that may also be beneficial in increasing backspin. More specifically, the '568 patent discloses a wedge hitting surface may take the form of an insert that includes a series of grooves, the design of which is varied from club to club to provide increasing friction with loft. Even more specifically, the wedges may utilize a club face of a constant surface roughness so that, regardless of club loft, the surface friction is kept constant and only the grooves of each club are varied to provide the changing impact friction required to provide constant spin rate.
U.S. Pat. No. 5,437,088 to Igarashi for a Method of Making a Golf Club that Provides Enhanced Backspin and Reduced Sidespin ('088 patent) also discloses a groove configuration that achieves increased backspin of a golf ball. More specifically, the '088 patent discloses an improved golf club wherein the surface of the face of the club is substantially flat, which is achieved by surfacing (milling) the club face, and wherein the edges of scoring lines (grooves) are made relatively sharp as a result of the surfacing operation. The sharp groove edges (and milling lines) of the present invention produce enhanced backspin and reduced sidespin when a golf ball is struck, which results in a relatively straight golf ball flight path, notwithstanding a glancing club impact angle.
As it can be seen from above, numerous attempts have been made to improve the backspin of a golf ball, especially when being hit with a wedge type golf club. However, the current methodology of utilizing either a surface treatment or groove configurations does not maximize the inherent potential of a wedge type golf club. More specifically, the current methodology does not take in to consideration the potential backspin and out going ball speed benefits that can be achieved by a wedge type golf club if the center of gravity (CG) location is shifted towards an alternate location that maximizes the efficiency of energy transfer between the wedge type golf club head and a golf ball.
FIG. 1, shows an exemplary wedge 100 in accordance with a prior art wedges wherein the location of the center of gravity (CG) 102 is at a distance d1 away from the ground 106. As shown FIG. 1, distance d1 denotes the location of the CG 102 of wedge 100 being a significant distance away from the ground 106. Distance d1, as shown in this exemplary prior art embodiment may generally be greater than 20 mm; however prior art wedges could have distance d1 be 21 mm, 22 mm, 23 mm, or any CG 102 location distance that is relatively high within a wedge without departing from exemplary prior art wedge 100.
Having a CG 102 location that is so high above ground 106 may generally be undesirable as it does not maximize the efficiency of energy transfer between the wedge type golf club head 100 and a golf ball. In order to maximize the efficiency of energy transfer between the wedge type golf club head 100 and a golf ball, it is generally desirable to have the CG 102 in closer proximity to the ground 106, and more preferably along an axis of impact perpendicular to the hitting surface that runs through the CG of the golf club and the center of the golf ball.
In addition to the increased backspin benefits that can be achieved by maximizing the CG location of a wedge type golf club, maximizing the CG location will also allow for increased performance characteristics such as increased ball speed and increased launch angle that correlates into increased trajectory, increased accuracy, and increased control. Increased ball speed will yield increased shot distance. If an increased spin is desired while keeping shot distance constant, the wedge loft will have to be increased, a characteristic which will mitigate the ballspeed increase while adding even more backspin to the ball, yielding even more overall stopping power or accuracy.
With respect to the ability of the golf club head to have an increased topline thickness that varies with the loft of the golf club head to improve the performance of the wedge type golf club head, the prior art, U.S. Pat. No. 5,547,426 to Wood discloses a golf club head using progressively sized heads having slots of selected depths in the back of the golf club head. These golf club heads may have a progressive top edge thickness so that all top edge appear to have the same width in use, but it makes no attempt to utilize and adjust this variation in topline thickness to improve the moment of inertia of the golf club head.
Hence, it can be seen that there is a need in the field for a golf club that is capable of improving the backspin characteristics without the need to either adjust the grooves or provide surface treatment to the wedge type club face. More specifically, there is a need in the field for a wedge type golf club that is capable of optimizing the performance characteristics of a golf shot such as backspin, ball speed, and launch angle by utilizing strategically placed CG locations within the wedge type golf club. The CG optimized wedge type golf club head that has improved performance characteristics may then be used in conjunction with a wedge type golf club head with various grooves or surface treatments to further optimize the backspin characteristics of a wedge type golf club head.